Used this bed shelf for my phone. The shelf is 17 x 12.5 cm and is used for an iPhone 12 Pro Max. It is 68mm between the “legs” and thats a pretty good width for my bed which is FINNSNES from ikea.  

The plugs that attaches the legs with the shelf is flush with the surface of the shelf which I hope you can see on the pictures. I used pliers to attach the plugs.

I printed this with PLA and 0.15 mm layer height. 

All components is in the same file so I use copy and paste in PrusaSlicer. 

You need:

1x shelf bed

2x legs

4x plugs to attach the legs.